This invention is related to processes for the preparation of polyols in the presence of a heterogeneous catalyst. More specifically, this invention is related to processes for the preparation of stereo-regular, crystalline, isotactic poly(propylene oxide).
Poly(alkylene oxides) are useful as solvents, surfactants, metal cutting oils, hydraulic fluids and as chemical intermediates in the manufacture of polyurethanes.
Various methods are known for the preparation of poly(alkylene oxides). These methods generally comprise the polymerization of one or more asymmetrical epoxides in the presence of appropriate catalysts. For example, U. S. Patent 3,135,705 teaches that certain unsymmetrically substituted epoxides may be homopolymerized or copolymerized using as a catalyst an organoaluminum compound that has been reacted and/or complexed with water prior to being used as a catalyst. It was taught that the proper selection of an organo-aluminum compound reacted with water could result in the selective formation of either a crystalline polymer or an amorphous polymer. E. J. Vandenberg, J. Polym. Sci. B, 2, 525 (1969) discusses epoxide polymerization including useful catalysts and the stereochemistry of the polymers obtained.
The known catalyst systems capable of selectively producing stereoregular or crystalline polymers have various drawbacks including the expense or toxicity of the catalysts, undesirably slow rates of polymerization and the production of polymers with less than desirable characteristics.